Planning software is used by manufacturers to aid in the manufacturing process. Based upon the desired product output and the components needed for each product, the planning software generates a schedule of what components need to be manufactured and by when, and what materials need to be procured and by when. This schedule is generated based upon data stored in a database. The planning process is often complicated and, for complex products, can take many hours to complete.
A typical requirement imposed by the planning software is that it needs to do its processing based on a single consistent version of the database. If one process of the planning software is reading one version of the database while another process is reading an updated version of the database, serious errors, such as double counting, can occur. As a result, planning software requires that data be provided from a single frozen version of the database in order to operate properly.
As is well known, a database or a selected subset thereof can be frozen by obtaining exclusive locks on all of the tables in the database or the selective subset. Once locked, the tables can be processed by the planning software to carry out the planning process. However, as noted above, the planning process can take many hours to complete. Many companies, especially those having offices around the world, cannot afford to lock their tables for extended periods of time. Hence, locking tables in this manner is often not a viable solution.
Another possible solution is to simply make a copy of the database prior to running the planning software. The problem with this solution is that for large databases, the copying process itself can take several hours. During this time, the tables need to be locked to ensure a frozen state. As long as the tables are locked, no updates can be made. Hence, this solution suffers from the same shortcomings, albeit to a lesser degree, as the locking solution.
Based on the foregoing, it is clearly desirable to provide a mechanism for obtaining a single frozen version of the database, or a subset thereof, without locking tables in the database for an extended period of time.